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HBRIDGE Motor Driver Shield problem

Posted: Sat Jan 17, 2015 4:12 am
by micky
Hi I've bought the H BRIDGE shield to use on my Arduino UNO.

At the moment. I'm trying something simple, a 12v DC brushed motor.

I know that the motor runs on 12v, and draws 30ma on no load.

I have uploaded the sample sketch, however all that happens is that the motor turns about 3 revolutions and then stops.

The only way I can get it to do that is to power the UNO with 12v using a 12v transformer (down from 240v), leaving the jumper on the Bridge VIN to motor power.

If I power the shield directly, and remove the jumper, and power the UNO via the USB cable, nothing happens!

I don't want to power both the UNO and the H Bridge at 12v , and also leave the small jumper in place, that, I assume, would cook something.

Any suggestions as to what I'm doing wrong?

Thanks,

Mick

Re: HBRIDGE Motor Driver Shield problem

Posted: Sat Jan 17, 2015 4:32 am
by andrew
Hello Mick

You can power your system with 12V including the Arduino, just as we have done in the "DC Motor Hardware Setup" section of the quick start guide:
http://www.freetronics.com.au/pages/hbr ... tart-guide

Try the demo sketch and let us know how you get on. If the motor doesn't turn, it may use more current than you expect - check the specificaitiosn and adjust the current-limiting switch on the shield.

Or if you're happy with the current settings, if possible can you put a voltmeter on the motor output terminals on the shield and measure the output when the sketch is running?

Re: HBRIDGE Motor Driver Shield problem

Posted: Sat Jan 17, 2015 5:29 am
by micky
Hi johnb, thanks for the prompt reply,

I have been using your demo sketch, same results.

Using an amp meter on the motor, it pulls 30ma free running, the start-up current shouldn't be that much more.

Switching the current limiting switch doesn't seem to make any difference.

As you suggested, I put a voltmeter on the output terminals, the volt meter jumps to about 4.5v, them drops back to zero after a second(or a bit more?), It's not an expensive meter, so the refresh rate may or may not be fast enough to get an accurate reading in the very short time frame there is power going to the motor.

Mick.

Re: HBRIDGE Motor Driver Shield problem

Posted: Sat Jan 17, 2015 7:55 am
by andrew
micky wrote:Hi johnb, thanks for the prompt reply,

I have been using your demo sketch, same results.

Using an amp meter on the motor, it pulls 30ma free running, the start-up current shouldn't be that much more.

Switching the current limiting switch doesn't seem to make any difference.

As you suggested, I put a voltmeter on the output terminals, the volt meter jumps to about 4.5v, them drops back to zero after a second(or a bit more?), It's not an expensive meter, so the refresh rate may or may not be fast enough to get an accurate reading in the very short time frame there is power going to the motor.

Mick.
If you have the jumper on, a 12V supply, removed the USB cable from the Arduino and only 4.5V is coming out of the motor terminals then I'm afraid there's a fault with the shield. If you bought it from a retailer such as Jaycar they can replace it for you or email support@freetronics.com to organise a replacement.

Re: HBRIDGE Motor Driver Shield problem

Posted: Tue Oct 27, 2015 12:15 am
by puno126
I have a similar problem but my stepper motor runs well by using an adjustable current power supply which is a bench pwr supply (expensive one). The current limiter setting on the shield doesn't work.

This is how I set it up: set current on pwr supply to 1A and set hbridge current setting to 0.6A

The results is: Hbridge is still drawing 1A and my stepper motor is running but the ticking of the steps are hard than if was set up at 0.3A, way too much current necessary for it to run sweet.

So now I think the only solution for my case is to build a cheapo power supply with an adjustable current output.

Any suggestions???